diff --git a/extensions/signals.py b/extensions/signals.py
index e6f2d682..780abdd9 100644
--- a/extensions/signals.py
+++ b/extensions/signals.py
@@ -5,7 +5,6 @@ from django.dispatch import receiver
 import django.dispatch
 
 import extensions.models
-import extensions.tasks
 import files.models
 
 version_changed = django.dispatch.Signal()
diff --git a/extensions/tasks.py b/extensions/tasks.py
deleted file mode 100644
index e69de29b..00000000
diff --git a/extensions/templates/extensions/detail.html b/extensions/templates/extensions/detail.html
index 912d9e70..7c0ed8e4 100644
--- a/extensions/templates/extensions/detail.html
+++ b/extensions/templates/extensions/detail.html
@@ -5,6 +5,12 @@
 {% block page_title %}{{ extension.name }}{% endblock page_title %}
 
 {% block content %}
+  {% if extension.latest_version %}
+    {% with latest=extension.latest_version %}
+      {% include "files/components/scan_details.html" with file=latest.file %}
+    {% endwith %}
+  {% endif %}
+
   {% has_maintainer extension as is_maintainer %}
   {% with latest=extension.latest_version %}
 
diff --git a/files/admin.py b/files/admin.py
index e6306157..8c8fa1bc 100644
--- a/files/admin.py
+++ b/files/admin.py
@@ -1,6 +1,28 @@
 from django.contrib import admin
+import background_task.admin
+import background_task.models
 
-from .models import File
+from .models import File, FileValidation
+import files.signals
+
+
+def scan_selected_files(self, request, queryset):
+    """Scan selected files."""
+    for instance in queryset:
+        files.signals.schedule_scan(instance)
+
+
+class FileValidationInlineAdmin(admin.StackedInline):
+    model = FileValidation
+    readonly_fields = ('date_created', 'date_modified', 'is_ok', 'results')
+    extra = 0
+
+    def _nope(self, request, obj):
+        return False
+
+    has_add_permission = _nope
+    has_change_permission = _nope
+    has_delete_permission = _nope
 
 
 @admin.register(File)
@@ -9,13 +31,14 @@ class FileAdmin(admin.ModelAdmin):
     save_on_top = True
 
     list_filter = (
+        'validation__is_ok',
         'type',
         'status',
         'date_status_changed',
         'date_approved',
         'date_deleted',
     )
-    list_display = ('original_name', 'extension', 'user', 'date_created', 'type', 'status')
+    list_display = ('original_name', 'extension', 'user', 'date_created', 'type', 'status', 'is_ok')
 
     list_select_related = ('version__extension', 'user')
 
@@ -77,3 +100,56 @@ class FileAdmin(admin.ModelAdmin):
             },
         ),
     )
+
+    inlines = [FileValidationInlineAdmin]
+    actions = [scan_selected_files]
+
+    def is_ok(self, obj):
+        return obj.validation.is_ok if hasattr(obj, 'validation') else None
+
+    is_ok.boolean = True
+
+
+try:
+    admin.site.unregister(background_task.models.Task)
+    admin.site.unregister(background_task.models.CompletedTask)
+except admin.site.NotRegistered:
+    pass
+
+
+class TaskMixin:
+    """Modify a few properties of background tasks displayed in admin."""
+
+    def no_errors(self, obj):
+        """Replace background_task's "has_error".
+
+        Make Django's red/green boolean icons less confusing
+        in the context of "there's an error during task run".
+        """
+        return not bool(obj.last_error)
+
+    no_errors.boolean = True
+
+
+@admin.register(background_task.models.Task)
+@admin.register(background_task.models.CompletedTask)
+class TaskAdmin(background_task.admin.TaskAdmin, TaskMixin):
+    date_hierarchy = 'run_at'
+    list_display = [
+        'run_at',
+        'task_name',
+        'task_params',
+        'attempts',
+        'no_errors',
+        'locked_by',
+        'locked_by_pid_running',
+    ]
+    list_filter = (
+        'task_name',
+        'run_at',
+        'failed_at',
+        'locked_at',
+        'attempts',
+        'creator_content_type',
+    )
+    search_fields = ['task_name', 'task_params', 'last_error', 'verbose_name']
diff --git a/files/migrations/0005_rename_validation_filevalidation_results_and_more.py b/files/migrations/0005_rename_validation_filevalidation_results_and_more.py
new file mode 100644
index 00000000..21d01245
--- /dev/null
+++ b/files/migrations/0005_rename_validation_filevalidation_results_and_more.py
@@ -0,0 +1,40 @@
+# Generated by Django 4.2.11 on 2024-04-12 09:05
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('files', '0004_alter_file_status'),
+    ]
+
+    operations = [
+        migrations.RenameField(
+            model_name='filevalidation',
+            old_name='validation',
+            new_name='results',
+        ),
+        migrations.AlterField(
+            model_name='filevalidation',
+            name='results',
+            field=models.JSONField(),
+        ),
+        migrations.RemoveField(
+            model_name='filevalidation',
+            name='errors',
+        ),
+        migrations.RemoveField(
+            model_name='filevalidation',
+            name='notices',
+        ),
+        migrations.RemoveField(
+            model_name='filevalidation',
+            name='warnings',
+        ),
+        migrations.RenameField(
+            model_name='filevalidation',
+            old_name='is_valid',
+            new_name='is_ok',
+        ),
+    ]
diff --git a/files/models.py b/files/models.py
index 246542cd..1d6f2d02 100644
--- a/files/models.py
+++ b/files/models.py
@@ -206,11 +206,8 @@ class File(CreatedModifiedMixin, TrackChangesMixin, SoftDeleteMixin, models.Mode
 
 
 class FileValidation(CreatedModifiedMixin, TrackChangesMixin, models.Model):
-    track_changes_to_fields = {'is_valid', 'errors', 'warnings', 'notices', 'validation'}
+    track_changes_to_fields = {'is_ok', 'results'}
 
     file = models.OneToOneField(File, related_name='validation', on_delete=models.CASCADE)
-    is_valid = models.BooleanField(default=False)
-    errors = models.IntegerField(default=0)
-    warnings = models.IntegerField(default=0)
-    notices = models.IntegerField(default=0)
-    validation = models.TextField()
+    is_ok = models.BooleanField(default=False)
+    results = models.JSONField()
diff --git a/files/signals.py b/files/signals.py
index 239506c9..3388efad 100644
--- a/files/signals.py
+++ b/files/signals.py
@@ -1,7 +1,12 @@
-from django.db.models.signals import pre_save
+import logging
+
+from django.db.models.signals import pre_save, post_save
 from django.dispatch import receiver
 
 import files.models
+import files.tasks
+
+logger = logging.getLogger(__name__)
 
 
 @receiver(pre_save, sender=files.models.File)
@@ -9,3 +14,19 @@ def _record_changes(sender: object, instance: files.models.File, **kwargs: objec
     was_changed, old_state = instance.pre_save_record()
 
     instance.record_status_change(was_changed, old_state, **kwargs)
+
+
+def schedule_scan(file: files.models.File) -> None:
+    """Schedule a scan of a given file."""
+    logger.info('Scheduling a scan for file pk=%s', file.pk)
+    files.tasks.clamdscan(file_id=file.pk, creator=file, verbose_name=file.source.name)
+
+
+@receiver(post_save, sender=files.models.File)
+def _scan_new_file(
+    sender: object, instance: files.models.File, created: bool, **kwargs: object
+) -> None:
+    if not created:
+        return
+
+    schedule_scan(instance)
diff --git a/files/tasks.py b/files/tasks.py
new file mode 100644
index 00000000..8468d384
--- /dev/null
+++ b/files/tasks.py
@@ -0,0 +1,36 @@
+import logging
+import os.path
+
+from background_task import background
+from background_task.tasks import TaskSchedule
+from django.conf import settings
+
+import files.models
+import files.utils
+
+logger = logging.getLogger(__name__)
+
+
+@background(schedule={'action': TaskSchedule.RESCHEDULE_EXISTING})
+def clamdscan(file_id: int):
+    """Run a scan of a given file and save its output as a FileValidation record."""
+    file = files.models.File.objects.get(pk=file_id)
+    abs_path = os.path.join(settings.MEDIA_ROOT, file.source.path)
+    completed_process = files.utils.run_clamdscan(abs_path)
+    logger.info('File pk=%s scanned: exit code %s', file.pk, completed_process.returncode)
+    scan_result = {
+        'clamdscan': {
+            'args': completed_process.args,
+            'stdout': completed_process.stdout.decode(),
+            'stderr': completed_process.stderr.decode(),
+            'returncode': completed_process.returncode,
+        }
+    }
+    is_ok = completed_process.returncode == 0
+    file_validation, is_new = files.models.FileValidation.objects.get_or_create(
+        file=file, defaults={'results': scan_result, 'is_ok': is_ok}
+    )
+    if not is_new:
+        file_validation.results = scan_result
+        file_validation.is_ok = is_ok
+        file_validation.save(update_fields={'results', 'is_ok'})
diff --git a/files/templates/files/components/scan_details.html b/files/templates/files/components/scan_details.html
new file mode 100644
index 00000000..4a83d374
--- /dev/null
+++ b/files/templates/files/components/scan_details.html
@@ -0,0 +1,21 @@
+{% load common i18n %}
+{# FIXME: we might want to rephrase is_moderator in terms of Django's (group) permissions #}
+{% if perms.files.view_file or request.user.is_moderator %}
+  {% with file_validation=file.validation %}
+    {% if file_validation and not file_validation.is_ok %}
+      <section>
+        <div class="card pb-3 pt-4 px-4 mb-3 ext-detail-download-danger">
+          <h3>⚠&nbsp;{% trans "Suspicious upload" %}</h3>
+          {% blocktrans asvar alert_text %}Scan of the {{ file }} indicates malicious content.{% endblocktrans %}
+          <h4>
+            {{ alert_text }}
+            {% if perms.files.view_file %}{# Moderators don't necessarily have access to the admin #}
+              {% url 'admin:files_file_change' file.pk as admin_file_url %}
+              <a href="{{ admin_file_url }}" target="_blank">{% trans "See details" %}</a>
+            {% endif %}
+          </h4>
+        </div>
+      </section>
+    {% endif %}
+  {% endwith %}
+{% endif %}
diff --git a/files/templates/files/components/scan_details_flag.html b/files/templates/files/components/scan_details_flag.html
new file mode 100644
index 00000000..7b896fce
--- /dev/null
+++ b/files/templates/files/components/scan_details_flag.html
@@ -0,0 +1,10 @@
+{% load common i18n %}
+{# FIXME: we might want to rephrase is_moderator in terms of Django's (group) permissions #}
+{% if perms.files.view_file or request.user.is_moderator %}
+  {% with file_validation=file.validation %}
+    {% if file_validation and not file_validation.is_ok %}
+      {% blocktrans asvar alert_text %}Scan of the {{ file }} indicates malicious content.{% endblocktrans %}
+      <b class="text-danger pt-2" title="{{ alert_text }}">⚠</b>
+    {% endif %}
+  {% endwith %}
+{% endif %}
diff --git a/files/tests/test_signals.py b/files/tests/test_signals.py
new file mode 100644
index 00000000..a2d73122
--- /dev/null
+++ b/files/tests/test_signals.py
@@ -0,0 +1,112 @@
+import os
+import shutil
+import tempfile
+import unittest
+
+from background_task.models import Task
+from django.conf import settings
+from django.test import TestCase, override_settings
+
+from common.tests.factories.files import FileFactory
+import files.models
+import files.tasks
+
+
+@unittest.skipUnless(shutil.which('clamdscan'), 'requires clamdscan')
+@override_settings(MEDIA_ROOT='/tmp/')
+class FileScanTest(TestCase):
+    def setUp(self):
+        super().setUp()
+        self.temp_directory = tempfile.mkdtemp(prefix=settings.MEDIA_ROOT)
+
+    def tearDown(self):
+        super().tearDown()
+        shutil.rmtree(self.temp_directory)
+
+    def test_scan_flags_found_invalid(self):
+        test_file_path = os.path.join(self.temp_directory, 'test_file.zip')
+        test_content = (
+            b'X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*'  # noqa: W605
+        )
+        with open(test_file_path, 'wb+') as test_file:
+            test_file.write(test_content)
+
+        file = FileFactory(source=test_file_path)
+        self.assertFalse(hasattr(file, 'validation'))
+
+        # A background task should have been created
+        task = Task.objects.created_by(creator=file).first()
+        self.assertIsNotNone(task)
+        self.assertEqual(task.task_name, 'files.tasks.clamdscan')
+        self.assertEqual(task.task_params, f'[[], {{"file_id": {file.pk}}}]')
+
+        # Actually run the task as if by background runner
+        task_args, task_kwargs = task.params()
+        files.tasks.clamdscan.task_function(*task_args, **task_kwargs)
+
+        file.refresh_from_db()
+        self.assertFalse(file.validation.is_ok)
+        result = file.validation.results['clamdscan']
+        self.assertEqual(result['returncode'], 1)
+        stdout_lines = result['stdout'].split('\n')
+        self.assertIn(f'{file.source.name}: Win.Test.EICAR_HDB-1 FOUND', stdout_lines[0])
+        self.assertEqual(result['stderr'], '')
+
+    def test_scan_flags_found_invalid_updates_existing_validation(self):
+        test_file_path = os.path.join(self.temp_directory, 'test_file.zip')
+        test_content = (
+            b'X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*'  # noqa: W605
+        )
+        with open(test_file_path, 'wb+') as test_file:
+            test_file.write(test_content)
+
+        file = FileFactory(source=test_file_path)
+        # Make sure validation record exists before scanner runs
+        existing_validation = files.models.FileValidation(file=file, results={})
+        existing_validation.save()
+        self.assertTrue(hasattr(file, 'validation'))
+
+        # A background task should have been created
+        task = Task.objects.created_by(creator=file).first()
+        self.assertIsNotNone(task)
+        self.assertEqual(task.task_name, 'files.tasks.clamdscan')
+        self.assertEqual(task.task_params, f'[[], {{"file_id": {file.pk}}}]')
+
+        # Actually run the task as if by background runner
+        task_args, task_kwargs = task.params()
+        files.tasks.clamdscan.task_function(*task_args, **task_kwargs)
+
+        self.assertFalse(file.validation.is_ok)
+        file.validation.refresh_from_db()
+        result = file.validation.results['clamdscan']
+        self.assertEqual(result['returncode'], 1)
+        stdout_lines = result['stdout'].split('\n')
+        self.assertIn(f'{file.source.name}: Win.Test.EICAR_HDB-1 FOUND', stdout_lines[0])
+        self.assertEqual(result['stderr'], '')
+        self.assertEqual(existing_validation.pk, file.validation.pk)
+
+    def test_scan_flags_nothing_found_valid(self):
+        test_file_path = os.path.join(self.temp_directory, 'test_file.zip')
+        with open(test_file_path, 'wb+') as test_file:
+            test_file.write(b'some file')
+
+        file = FileFactory(source=test_file_path)
+        self.assertFalse(hasattr(file, 'validation'))
+
+        # A background task should have been created
+        task = Task.objects.created_by(creator=file).first()
+        self.assertIsNotNone(task)
+        self.assertEqual(task.task_name, 'files.tasks.clamdscan')
+        self.assertEqual(task.task_params, f'[[], {{"file_id": {file.pk}}}]')
+
+        # Actually run the task as if by background runner
+        task_args, task_kwargs = task.params()
+        files.tasks.clamdscan.task_function(*task_args, **task_kwargs)
+
+        file.refresh_from_db()
+        self.assertTrue(file.validation.is_ok)
+        result = file.validation.results['clamdscan']
+        self.assertEqual(result['returncode'], 0)
+        stdout_lines = result['stdout'].split('\n')
+        self.assertIn(f'{file.source.name}: OK', stdout_lines[0])
+        self.assertEqual(result['stderr'], '')
diff --git a/files/utils.py b/files/utils.py
index 3c4f413f..c0bb26ec 100644
--- a/files/utils.py
+++ b/files/utils.py
@@ -4,6 +4,8 @@ import io
 import logging
 import mimetypes
 import os
+import os.path
+import subprocess
 import toml
 import typing
 import zipfile
@@ -161,3 +163,12 @@ def guess_mimetype_from_content(file_obj) -> str:
     # This file might be read again by validation or other utilities
     file_obj.seek(0)
     return mimetype_from_bytes
+
+
+def run_clamdscan(abs_path: str) -> 'subprocess.CompletedProcess':
+    logger.info('Scanning file at path=%s', abs_path)
+    scan_args = ['clamdscan', '--fdpass', abs_path]
+    logger.info('Running %s', scan_args)
+    completed_process = subprocess.run(scan_args, capture_output=True)
+    logger.info('File at path=%s scanned: exit code %s', abs_path, completed_process.returncode)
+    return completed_process
diff --git a/playbooks/install.yaml b/playbooks/install.yaml
index 44840ccd..c625ae40 100644
--- a/playbooks/install.yaml
+++ b/playbooks/install.yaml
@@ -9,6 +9,8 @@
     - name: Installing required packages
       ansible.builtin.apt: name={{ item }} state=present
       with_items:
+        - clamav-daemon
+        - clamdscan
         - git
         - libpq-dev
         - nginx-full
diff --git a/reviewers/templates/reviewers/components/review_list_item.html b/reviewers/templates/reviewers/components/review_list_item.html
index 0bbe5b15..8de1cfb5 100644
--- a/reviewers/templates/reviewers/components/review_list_item.html
+++ b/reviewers/templates/reviewers/components/review_list_item.html
@@ -22,6 +22,7 @@
       <span>{{ extension.review_activity.all.last.date_created|naturaltime_compact }}</span>
     </a>
     {% endif %}
+    {% include "files/components/scan_details_flag.html" with file=extension.latest_version.file %}
   </td>
   <td>
     <a href="{{ extension.get_review_url }}" class="text-decoration-none">